PO Box 259. HvnLon, Vic 3444 flJS7fitIA e www.cIademUXL.com * info@acodermyXL.com a business of Tent Snvvices PLv Ltd - RON 72 892 315 097 Fre 1800 637 640 InterE +61 3 54 232558 Fox & 03 54 232677 inter +61 3 54 232677 TRANSLATION VERIFICATION CERTIFICATE This is to certify that the attached document is an English translation of a - German Patent PCTIDE2005000243 and Academy Translations declare that the translation thereof is to the best of their knowledge and ability true and correct. September 12, 2006 Date Stamp/Signature; Multilingual Tschnical Documentotion Translalion front German of PCT Application PCT/DE200Q00243 Wheel guiding joint 5 Description The invention relates to a joint system for a wheel guiding mechanism, parLicularly a driven, steerable axle 10 of a motor vehicle according to the preamble of claim 1. Joint systems of the type described above are, for example, used for so-called "independent wheel suspensions" deployed in, among others, McPherson strut 15 axles, damper strut axles or twin control arm axles. Such independent wheel suspensions are characterised by a moveable insert, for example a steering knuckle, which carries out the actual steering movement being attached to a fixed part which is not moved by the steering. 20 Such independent wheel suspensions of for in particular the benefit that the steering axle around which the wheel is pivoted during the steering movement can he constructed with a smaller kingpin angle as well as being 25 closer to the central, level of the wheel without this leading to a larger than desired and/or positive offset steering. This decreases the interference to the steering caused by the drive torque or brake torque or from the unevenness of the road, imbalance of a wheel or 30 centrifugal, forces. Furthermore, in this way the entire axle geometry, in particular the interactions between kingpin angle, offset steering, wheel track and camber as well as caster can be better optimised in order to ensure 2 optimum vehicle control as well as sensitive tractability free of reaction forces under all driving conditions and in. as large a steering angle range as possible. 5 Such independent wheel suspensions are, for example, found in the documents US 6,042,294 Al and US 6,010,272 Al. These known wheel supports include two ball joints which determine the steering axis or swivel axis of the steering knuckle. The steering knuckle can 10 therefore, according to the claims in those documents, unlike the yoke-type joint system at the wheel supports, be swung around the steering axis determined by the two ball joints, which causes the corresponding wheel of the vehicle to experience a steering movement. 15 However, the wheel guiding joint formed by the two ball joints must necessarily and in all cases be designed as a combination of a fixed bearing and a self-adjusting bearing so that the unavoidable manufacturing and 20 installation tolerances and the deformation of the joint components and axle components during operation can be accommodated. This applies all the more as such wheel guiding joints generally have to be built as a split component in order to allow the drive shaft for the wheel 25 to pass through. This open, split design results, however, in additional elasticity, which manifests itself in deformation of the joint yoke or the corresponding bearing support as soon they are loaded by drive forces, brake forces and centrifugal forces. 30 Combinations of a fixed bearing with a self-adjusting bearing are, however, often problematic, in particular because both tilting and axial deviations of the self- 3 adjusting bearing have to be accommodated. In order to accommodate both tilting and axial deviations of a shaft or axle, it is, according to the prior art, necessary to provide two different bearing surface areas for the self 5 adjusting bearing. of those, one of the bearing surface areas is specifically provided to accommodate the tilting and the other bearing surface area for accommodating the axial 10 deviations. in the present case of a wheel guiding joint including two ball joints this means that one of the ball joints would have to be equipped with a provision for the 15 accommodation of axial deviations of the ball pin and of the ball socket with respect to the bearing housing. This provision for the accommodation of axial deviations results in the necessity of providing a further bearing surface which is largely prismatic in addition to the 20 spherical bearing surfaces between ball pin and ball socket This additionally required bearing surface, however, results in considerable design costs and, of course, it 25 requires additional space, of which, however, very little is available close Lo Lhe wheel guiding joint under discussion, which is usually accommodated within the wheel rim. Furthermore, the necessary bearing surface required for accommodating the axial deviation will lead 30 to additional radial bearing play in the joint system, which in turn often results in costly design compensation measures.
4 With this background, it is the object of the present invention to create a joint design which can surmount the listed disadvantages. The joint design should, in particular, simplify the design required for the 5 simultaneous accommodation of axial deviations and tilting between the individual joint components. In addition, the joint design should be as space-efficient as possible, play-free and low-maintenance, as well as low-cost in manufacture. 10 This object is met by a joint design with the characteristics of claim 1. The preferred embodiments are the subject of the sub 15 claims. The joint design according to the present invention includes a joint yoke which is connecLcd in the familiar way to a vehicle axle or a wheel carrier as a steering knuckle accommodating the wheel bearing. Joint yoke and steering knuckle are connected so as to be 20 swivelable via two axially aligned bearings via which the vehicle wheel receives the steer.tng movement. According to the invention the joint design is characterised by at least one of the two bearings 25 providing a swivelable connection between the joint yoke and the steering knuckle being equipped by a toroidal roller bearing. In other words, this means that in particular the self 30 adjusting bearing in the joint design is formed by a toroidal. roller bearing. For the nature of the invention it is not relevant wbat kind of fixed bearing is used in the joint design as long as the fixed bearing can, as 5 intended, support all of the axial forces in the joint design and transmit them botwoon the steering knuckle and the joint yoke. 5 Among all the roller bearings, toroidal roller bearings have the unique property of being able to accommodate both axial displacement and angular error simply by automatic relative movement of inner ring, outer ring and roller elements. For this reason, neither the frictional 10 forces familiar from the conventional self-adjusting bearing, nor the stick--slip effects in the case of axial displacements, which in turn lead to undesired vibrations or loading of the roller bearing surfaces, occur. 15 Furthermore, the described compensating movements of the bearing components of the toroidal roller bearing are not associated with an uneven contact pressure or even harmful edge pressure of the roller elements. 20 At Lho same time, the toroidal roller bearing also offers, on account of the continuoussly uniform line contact between the toroidal-concave bearing rings and the convex roller elements, an extremely high load bearing capacity. In addition, independent of angular 25 displacements or axial displacements, toroidal roller bearings are almost free of play on account of their special geometry, and this benefits the running smoothness of the wheel and gives freedom from reactive forces in the steering. 30 The big advantage in deploying a toroidal roller bearing according to the invention as the self-adjusting bearing in a joint design for wheel guidance is that all angle 6 displacements occurring within the wheel guiding joint, for example on account of tolerances or on account of deformation caused by loading as it occurs during operation of the vehicle, can be accommodaLed with a 5 single bearing surface. The additional prismatic bearing surface previously always necessary with the prior art for the accommodation of axial displacements near the self-adjusting bearing can be completely omitted. 10 At the same time, the costs and the great constructive effort associated with this additional bearing surface are also no longer required. In addition, a considerable amount of space is saved, which allows the joint design according to the invention also to be deployed in smaller 15 vehicles or with smaller inner rim diameters. Last but not at least, therefore, the radial bearing play associated with the previously required additional bearing surface also disappears, which considerably improves the running smoothness, freedom from maintenance 20 and the service life of the vehicle axle constructed like this. The design of the other bearing forming the fixed bearing of the joint design is free, as long as this other 25 bearing point can accommodate and transmit all the axial forces in the joint between the joint yoke and the steering knuckle. According to one of the preferred embodiments of the invention, the fixed bearing is, however, designed as a ball joint. As this ball joint as 30 a fixed bearing does not have to accommodate any axial displacement, it can be built space-efficiently and robustly as well as having low-play and with a high load bearing capacity.
7 According to a further preferred embodiment of the invention, the toroidal roller bearing is seated in a cup-shaped seat in the joint yoke or the steering 5 knuckle, with the cup-shaped seat preferably having a continuous ring collar in the area of the bottom of the seat. This arrangement is advantageous insofar as Lhe toroidal roller bearing receives a defined location simply by pressing it into the cup-shaped seat with the 10 toroidal roller bearing on the bottom side being completely separated from the surroundings by the bottom of the seat. The continuous ring collar ensures a defined axial seat for the toroidal roller bearing in the cup shaped seat. In addition, in this way it is ensured that 15 the space required for the inner ring for accommodating the axial displacement is maintained, as is that for the end of the joint pin of the steering knuckle. Furthermore this cavity can be used as an additional reservoir for holding lubricant for the toroidal roller bearing. 20 In order to further improve the comfort properties and service life of the joint design in a further embodiment of the invention, it is planned that between the outer ring of the toroidal roller bearing and the essentially 25 cylindrical wall of the toroidal roller bearing cup shaped seat, at least one elastic element be installed. This at least one elastic element, preferably in the form of one or more elastic rings of essentially circular cross section, leads to a certain vibration damping and 30 uncoupling between the steering knuckle and joint yoke. This also benefits driving comfort and reduces the noise in a vehicle axle fitted with the joint design. The elastic ring or rings can here in particular be made to g fit into grooves which are provided continuously in the surface of the outer ring and/or in Lhc internal surface of the wall of the cup-shaped seat. 5 According to a further preferred embodiment of the invention, the toroidal roller bearing is covered with a seal on the side which is not lying against the bottom of the cup-shaped seat. In this case, the seal will separate both the roller elements and bearing surfaces of the 10 toroidal roller bearing as well as the gap between the outer bearing ring and the cup-shaped seat and the gap between the inner bearing ring and the bearing pin from environmental influences. This is advantageous because only with a seal can the entire self-adjusting bearing 15 area be fully protected and encapsulated. Particularly preferred is a seal with a first and a second edge or sealing lip in the inner circumference area. In this case the seal will press with the first 20 edge or sealing lip radialy against the bearing pin. This leads to a particularly effective and secure separation of the toroidal. roller bearing from all. environmental influences, in particular even when during operation of the joint design axial displacement occurs 25 between the steering knuckle and the joint yoke in the toroidal roller bearing. The invention is explained in more detail. below by means of an illustration simply showing one example of an 30 embodiment. It shows Figure 1 as a schematic depiction of an embodiment of a joint design according to the invention viewed from the side and with part section.
9 In figure 1 an embodiment of the joint design according to the invention as viewed in the driving direction of the vehicle it belongs to. Only the very schematic arrangement is shown consisting of a joint yoke 1 and a 5 steering knuckle 2, with the arrangement illustrated neither to the correct scale nor with correct angles. Joint yoke 1 on the left-hand side of the drawing is joined, for example, to a spring strut (not shown), while steering knuckle 2 on the right-hand side of the drawing 10 is fitted to the bearing of the steered wheel at 3 (also not illustrated). Joint yoke 1 and steering knuckle 2 have two common bearing points 4 and 5, with one of the bearing points realised as a ball joint 4 and the other bearing point being fitted with a roller bearing 5. 15 In this case the roller bearing is designed as a toroidal roller bearing which, as described above, can accommodate both a certain degree of angular displacement between its outer ring 6 and its inner ring 7 and axial displacement 20 of the inner ring 7 with respect to the outer ring 6 without problems and without causing reaction forces. The ball bearing 4 is, in contrast, formed by the fixed bearing in the fixed and self-adjusting bearing 25 combination shown and is responsible for the absorption and transmission of the forces acting in the direction of the joint axis between the steering knuckle 2 and the joint yoke 1. 30 During the operation of a vehicle, in the area of the wheel and the axle considerable forces and torques occur which, among other sources, originate from the drive force of the vehicle, from the centrifugal forces while 10 driving through curves, from the brake torque during braking or from the effect of the unevenness of the road. These forces and bending moments must be absorbed by the 5 steering knuckle 2 and be transmitted to joint yoke 1. However, both in the sLeering knuckle 2 itself and in the joint yoke 1 not inconsiderable elastic deformations occur. These result in the bending of the joint axle 8, in axial offsets or eccentricities of the axes of the two 10 joints 4, 5, as well as the elastic opening of joint yoke 1, which in particular leads to an increase in the distance between the two joints 4, 5. In addition, the unavoidable tolerances in the components 15 have to be accommodated as well as the additional tolerances originating in the fitting of the joint design. Al. of these misalignments, deformations and displacements can be accommodated without difficulty by the self-adjusting bearing 5, realised by a toroidal 20 roller bearing, without the occurrence of reaction forces or even edge pressure, which represent additional loads on the components and would reduce their service life. Figure 1 also shows that the embodiment of the self 25 adjusting bearing 5 as a toroidal roller bearing can be particularly space efficient. In particular, compared to the prior elaborate ball joints with axial compensation, in this way considerable 30 space can be saved. This also allows the deployment of the joint design according to the invention in smaller vehicles or with smaller rim diameters.
The size reduction, according to the invention, of the dimensions of the self-adjusting bearing mainly depends on the fact that the toroidal roller bearing has an extremely high specific load bearing capacity and can 5 therefore be dimensioned relatively small. In addition, the reduction in the constructive space results from the fact that both angular displacements and axial displacements can be accommodated by the same arrangement of bearing surfaces of the toroidal roller bearing in 10 contrast to the ball joints. This design has the specific advantage of high rigidity and, in addition, the side of the toroidal roller bearing opposite to the pin, (at the bottom edge on the drawing) is completely covered so that no further sealing on this side is required. 15 Figure 1 also shows that between the outer ring 6 of the toroidal roller bearing and the cylindrical wall of the cap-shaped seat 9, an elastic element 10 can be fitted, for example one or more elastic rings 10. The elastic 20 element 10 can in this way further improve the vibrational decoupling between steering knuckle 2 and joint yoke 1 and ensure a better cushioning of loading peaks. Furthermore, in this way the transmission of tyre noise as structure-born noise via the joints in the wheel 25 suspension can be reduced or muffled. Finally, figure 1 also shows the type and design of the seal 11 which covers the entire bearing area of the self adjusting bearing 5 on the steering knuckle side. The 30 seal 11 shown is insofar particularly advantageous as in this way both the bearing surfaces and the bearing elements in the toroidal roller bearing are completely protected as are the gaps 12 and 13 between the bearing 12 rings 6 and 7 of the toroidal roller bearing and the corresponding press fit for the bearing rings 6 and 7 in the cup-shaped seat 9 or on the bearing pin 14 on steering knuckle 2 which are potentially prone to 5 corrosion. The seal 11 is supported in the area of the steering knuckle bearing pin 14 both radially at 12 by the bearing pin 14 as well as axially at 15 by the collar of the 10 bearing pin 14. This leads on the one hand to a particularly secure sealing effect and ensures on the other hand that the seal 11 makes reliable contact with the corresponding sealing surfaces 12, 13 arid 15 under all operating conditions, in particularly when the joint 15 axle 8 is bent and/or axial displacements have taken place between the bearing pin 14 and the joint yoke 2. As a result it becomes clear, therefore, that, thanks to the invention, the structure of joint designs for whccl 20 suspensions, in particular for steerable, driven axles of vehicles, can be considerably simplified and improved. The constructive cost for such a joint design is reduced as is the space required for the joint design according to the invention, furthermore a considerably improved 25 service life, reduced maintenance requirements and improved comfort features are to be expected. Despite the improvements made on account of the invention, thanks to the invention, cost savings during the design, manufacture and operation of wheel suspensions and axle 30 systems can be made. The invention Lherefore contributes considerably to the improvement of the wheel guidance and to optimisation of 13 the axle kinematics, which in turn benefits safety, cost efficiency, low maintenance requirements and the driving comfort of the wheel suspensions for vehicles.
14 Reference number list 1 Joint yoke 5 2 Steering knuckle 3 Wheel bearing 4 Ball joint 5 Roller bearing 6 Outer ring 10 7 Inner ring 8 Joint axis 9 Seat 10 Elastic element 11 Seal 15 12 Sealing surface 13 Sealing surface 14 Bearing pin 15 Collar on the bearing pin